Energy charged capacitor

It is easily imaginable to be able to accumulate the electrical energy in the
capacitor. However, this is also temporary. Because the insulation
resistance of the capacitor is a value of not infinity but limited, energy is
lost by a natural electrical discharge. The electrical energy cannot be saved
for a long term like the battery in a word.

Calculation of energy charged capacitor with

Now, the voltage e [V] on the charged capacitor C [F] on the charge q
[coulomb] Assume that is even saved.

q = C*e or e = q/C --- Expression (1)

A further small charge capacitor ⊿q [Coulomb] consider that charge.

⊿U = e*⊿q ---- Expression (2)

It becomes it. The energy charged the capacitor with U [J] is charge as for
the expression (2) From 0 It obtains if it integrates into Q by
q.

U = ∫0Q
e*dq = ∫0Q
(q/C)dq = Q2/2C --- Expression (3)

U [J] of the voltage capacitor charged E [V] with electrical energy of C[F]
is as follows. From Q = CE

U = (1/2)CE2 --- Expression (4)

It becomes it.

Notes when it charges capacitor from DC power

If it charges the capacitor from the constant-voltage source, energy becomes
half.

In this case, the energy of the capacitor becomes half of the energy supplied
from DC power though might it charge the capacitor from DC power and this energy
be used.

In a word, the energy supplied from the DC power of E [V] though the energy
charged the capacitor with by the above-mentioned expression (4) is obtained
Us [J] :.

Us = QE = CE2 ---- Expression (5)

Vicinity (4) type becomes half energy of the expression (5).

Where did this lost energy go?It has been consumed by the resistance of
wiring. Even if this resistance is unlimitedly adjusted to 0, the half of energy
is consumed by minute resistance. In this case, the charging current becomes
infinity momentarily at the time of switched on.

Then, 0 does lose the resistance of the coil and wiring and if it is a method
of the charging current's not becoming infinity, is not lost energy either?It
thinks about the thing with which it charges with the circuit that connects the
coil of the ideal between the power supply and the capacitor of the ideal now.

In this case, the capacitor resonates to the coil in parallel and the voltage
of the capacitor comes and goes from 0 between twice the power-supply voltage
indefinitely though the value of the current is limited. It settles down
gradually actually in the power-supply voltage the value of the capacitor
because there is minute resistance. The half of energy is still lost as for
this.

Method of reducing a decrease in energy even if it charges capacitor

It exists in the capacitor, and it is an equipment using the electrical
charge and discharge of the capacitor and the thing of the efficiency 50% or
more will not exist in this world if energy is sure to become half if the
electrical charge and discharge is repeated.

The method by which energy is not lost even if it charges the capacitor is to
always charge it by almost the same voltage as the capacitor. Resistance is not
used like turning on switching type DC-DC converter power supply and the
capacitor is charged gradually. The voltage rises gradually when the movement of
the DC-DC converter is seen with the oscilloscope though it is momentary.

There is a method by which energy is not lost even if it theoretically
charges the capacitor. It is a method of the connection of the coil of the ideal
to the constant-voltage source of the above-mentioned ideal and the charge to
the capacitor.

When the voltage of the capacitor at this time increases to twice that of the
power-supply voltage first (The current at this time is 0) If the circuit is
separated, the capacitor can be charged without the loss. It is a unexamination
whether this method is feasible.

It thinks about the circuit that charges with the capacitor when it
stockpiles one's energy in the coil like the switching power supply of the fly
backing converter type, and this energy is opened. When the energy of this coil
was opened, it charged it if it connected it with the capacitor with the diode
because the voltage was irregular by the same voltage as the capacitor.

Is it wrong anywhere though doesn't think that energy is theoretically lost
if it is this method?

Application of energy accumulated in capacitor

What's useful and what is stored capacitor energy.

The capacitor is used for the output side without fail for the DC power
devices other than the battery. And, the energy accumulated in the capacitor is
used.

The resonance happens when the capacitor is connected with the coil and the
energy of the capacitor and the energy of the coil are exchanged. This is used
as a series resonance and a parallel resonance.

The energy accumulated in the capacitor is discharged to the coil at a dash,
and there are a machining and a coil gun, etc. that use the electromagnetic
force for the one converted into mechanical energy. Moreover, there is a device
that discharges the energy of the capacitor to the primary side of the
transformer at a time and causes the high pressure on the second side. It is
used for the blitz device in the ignition device and the electrified fence that
is called CDI of the car etc.

Discharging the energy charged the capacitor with to the xenon lamp at a
time and emitting light are the flashes of the camera.

In addition, the thing using the capacitor uses the energy accumulated in
the capacitor in some shape.

Author:
Dai IshikawaI am a Business owner of as76.net, and a Engineer.